Elliptical spring



(No Model.)-

E. & J. J. LAASS. ELLIPTICAL SPRING.

PatentedLMar. 27, 1894.

STATES PATIENT Fries.

EMIL LAASS AND JOHN J. LAASS, OF SYRACUSE, NEW YORK.

ELLIPTICAL SPRING.

SPECIFICATION forming part of Letters Patent N 0. 517,106, dated March 27, 1894. Application filed June 16 1893. Serial No. 477.792. (No model.)

To all whom it may concern:

Be it known that we, EMIL LAASS and JOHN J. LAnss, of Syracuse, in the county of Onondaga,1n the State of New York, have invented new and useful Improvements in Elliptical Springs, of which the following,- taken in connection with the accompanying drawings, is a full, clear, and exact description.

Thls lnvention relates to elliptic springs deslgned more especially for supporting seats on wagons. And the invention consists of an elliptic spring formed in one piece of a springmetal plate slitted longitudinally between its end portions and having the alternate intermediate strips bowed in uniform arches in opposite directions from each other, so that each of said strips shall have its bearing in the center of the length thereof and thus cause the strain to be uniformly distributed throughoutthelengthsof the respective strips. And the invention also consists in terminatmg the slits in rounded openings which serve to prevent the plate from splitting beyond the ends of the slits. And the invention furthermore consists in a novel construction of a graduated elliptic spring formed in one piece as aforesaid. All as hereinafter more fully described and specifically set forth in the claims.

In the annexed drawings Figure 1 is a plan view of a section of steel plate or band from which our improved spring is formed. Fig. 2 1s a plan view of a blank formed from the aforesaid plate or band. Fig. 3 is a side view of an elliptic spring embodying our invention. Fig. 4. is a plan View of another blank from whloh our improved spring may be formed. Flgs. 5 and 6 are side views of the end portlons of springs embodying our invention. Flg. is a plan View of a blank from which our lmproved graduated elliptic spring is formed, and Fig. 8 is a side view of said spring.

Similar letters of reference indicate corresponding parts.

A- represents the section of steel plate or band from which we form our improved elliptic spring in one piece. In the construction of said spring we slit the steel band -A, longitudinally between its ends as shown at -C&'-=tt'-- in either of the Figs. 2, 4. or 7 of the drawings according to the size and strength required of the spring. For seatsprings for wagons we prefer to provide the blank withtwo parallel longitudinal slits-a -a' and thus form three strips of steel side byside. In bending the blank into requisite elliptic shape we bow the central strip bin opposite direction fromthe side-strips a a-- and thus impart to the blank the shape shown in Fig. 3 of the drawings. For a heavier spring we employ a Wider blank and provide the same with at least fourlongitudinal slits a'-a'a-a-, and bow the central strip band two outside strips bb in opposite direction from the intermediate strips a --a-. The side view of this spring will present the same appearance shown in Fig. 3 of the drawings. To guard against the binding of the adjacent edges of the strips aand bwhen the spring is subjected to a load we terminate the slits a/- a', in enlarged openings bb-. The outer ends of these openings we prefer to terminate nearly or quite semi-circular and thereby guard against the splitting of the spring from the slits, a-a' through the ends of the spring. Wide springs may be reinforced by folding the ends of the spring transversely as represented at c and -c in Figs. 6 and 5 of the drawings.

To form a graduated elliptic spring we provide the blank A-, with at least four longitudinal slits two of which (preferably the two central) are shorter than the other slits. The two outer strips a-a are bowed in opposite direction from the adjacent strips b b and the short central strip -d is bowed back or in opposite direction from the adjacent strips b-b-. The spring thus receives the shape shown in Fig. 80f the drawings.

In the operation of this spring theload first depresses the longer or main portions a bof the spring, and if the load is increased the said main portions are sufficiently com pressed to bring the load to bear on the auxiliary short portion dof the spring which is thus reinforced. In every instance each strip of the spring plate is bent in uniform arch shape to form the bearing-surface in the center of the length thereof and thus distribute the strain uniformly over the entire lengths of the strips.

WVhat we claim as our invention is 1. An elliptic spring formed in one piece of spring-plate slitted longitudinally between its end portions and having each intermediate strip bent in opposite direction from the ad- Jacent strip or strips and in uniform archshape to form the hearings in the centers of the respective strips as set forth.

2. An elliptic spring formed in one piece of spring-plate slitted longitudinally between its end portions and having said slits terminated in enlarged rounded openings to prevent splitting of the plate from the slits outward, each intermediate strip of said plate being bent in opposite direction from the adjacent strip or strips and in uniform archshape to form central bearings on the respective strips as set forth.

3. As a new article of manufacture a graduated elliptic spring formed in one piece of steel band slitted longitudinally between its ends, the two central slits being shorter than the outer slits, and the strip between the short slits being bowed in opposite direction from the adjacent longer strips substantially as set forth and shown.

In testimony whereof we have hereunto signed our names this 5th day of June, 1893.

EMIL LAASS. [L. s.] JOHN J. LAASS. [L. s]

Witnesses:

H. M. SEAMANS, O. L. BENDIXON. 

